Socket 编程 UDP-EW帮帮网

以下都包含日志：日志代码如下(日志的讲解请翻看前文)

LockGuard.hpp

#pragma once

#include <pthread.h>

class LockGuard
{
public:
    LockGuard(pthread_mutex_t *mutex):_mutex(mutex)
    {
        pthread_mutex_lock(_mutex);
    }
    ~LockGuard()
    {
        pthread_mutex_unlock(_mutex);
    }
private:
    pthread_mutex_t *_mutex;
};

Log.hpp

#pragma once

#include <iostream>
#include <sys/types.h>
#include <unistd.h>
#include <ctime>
#include <cstdarg>
#include <fstream>
#include <cstring>
#include <pthread.h>
#include "LockGuard.hpp"

namespace log_ns
{

    enum
    {
        DEBUG = 1,
        INFO,
        WARNING,
        ERROR,
        FATAL
    };

    std::string LevelToString(int level)
    {
        switch (level)
        {
        case DEBUG:
            return "DEBUG";
        case INFO:
            return "INFO";
        case WARNING:
            return "WARNING";
        case ERROR:
            return "ERROR";
        case FATAL:
            return "FATAL";
        default:
            return "UNKNOWN";
        }
    }

    std::string GetCurrTime()
    {
        time_t now = time(nullptr);
        struct tm *curr_time = localtime(&now);
        char buffer[128];
        snprintf(buffer, sizeof(buffer), "%d-%02d-%02d %02d:%02d:%02d",
                 curr_time->tm_year + 1900,
                 curr_time->tm_mon + 1,
                 curr_time->tm_mday,
                 curr_time->tm_hour,
                 curr_time->tm_min,
                 curr_time->tm_sec);
        return buffer;
    }

    class logmessage
    {
    public:
        std::string _level;
        pid_t _id;
        std::string _filename;
        int _filenumber;
        std::string _curr_time;
        std::string _message_info;
    };

#define SCREEN_TYPE 1
#define FILE_TYPE 2

    const std::string glogfile = "./log.txt";
    pthread_mutex_t glock = PTHREAD_MUTEX_INITIALIZER;

    // log.logMessage("", 12, INFO, "this is a %d message ,%f, %s hellwrodl", x, , , );
    class Log
    {
    public:
        Log(const std::string &logfile = glogfile) : _logfile(logfile), _type(SCREEN_TYPE)
        {
        }
        void Enable(int type)
        {
            _type = type;
        }
        void FlushLogToScreen(const logmessage &lg)
        {
            printf("[%s][%d][%s][%d][%s] %s",
                   lg._level.c_str(),
                   lg._id,
                   lg._filename.c_str(),
                   lg._filenumber,
                   lg._curr_time.c_str(),
                   lg._message_info.c_str());
        }
        void FlushLogToFile(const logmessage &lg)
        {
            std::ofstream out(_logfile, std::ios::app);
            if (!out.is_open())
                return;
            char logtxt[2048];
            snprintf(logtxt, sizeof(logtxt), "[%s][%d][%s][%d][%s] %s",
                     lg._level.c_str(),
                     lg._id,
                     lg._filename.c_str(),
                     lg._filenumber,
                     lg._curr_time.c_str(),
                     lg._message_info.c_str());
            out.write(logtxt, strlen(logtxt));
            out.close();
        }
        void FlushLog(const logmessage &lg)
        {
            // 加过滤逻辑 --- TODO

            LockGuard lockguard(&glock);
            switch (_type)
            {
            case SCREEN_TYPE:
                FlushLogToScreen(lg);
                break;
            case FILE_TYPE:
                FlushLogToFile(lg);
                break;
            }
        }
        void logMessage(std::string filename, int filenumber, int level, const char *format, ...)
        {
            logmessage lg;

            lg._level = LevelToString(level);
            lg._id = getpid();
            lg._filename = filename;
            lg._filenumber = filenumber;
            lg._curr_time = GetCurrTime();

            va_list ap;
            va_start(ap, format);
            char log_info[1024];
            vsnprintf(log_info, sizeof(log_info), format, ap);
            va_end(ap);
            lg._message_info = log_info;

            // 打印出来日志
            FlushLog(lg);
        }
        ~Log()
        {
        }

    private:
        int _type;
        std::string _logfile;
    };

    Log lg;

#define LOG(Level, Format, ...)                                        \
    do                                                                 \
    {                                                                  \
        lg.logMessage(__FILE__, __LINE__, Level, Format, ##__VA_ARGS__); \
    } while (0)
#define EnableScreen()          \
    do                          \
    {                           \
        lg.Enable(SCREEN_TYPE); \
    } while (0)
#define EnableFILE()          \
    do                        \
    {                         \
        lg.Enable(FILE_TYPE); \
    } while (0)
};

次要共同代码：

Makefile

.PHONY:all
all:udpserver udpclient

udpserver:UdpServerMain.cc
	g++ -o $@ $^ -std=c++14
udpclient:UdpClientMain.cc
	g++ -o $@ $^ -std=c++14

.PHONY:clean
clean:
	rm -rf udpserver udpclient

nocopy.hpp (防止服务器被拷贝构造和赋值构造)(服务器具有唯一性)
#pragma once

class nocopy
{
public:
    nocopy(){}
    ~nocopy(){}
    nocopy(const nocopy&) = delete;
    const nocopy& operator=(const nocopy&) = delete;
};

V1 版本 - echo server

简单的回显服务器和客户端代码

InetAddr.hpp (客户端记载用户信息如ip，端口号和结构体)

#pragma once

#include <iostream>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

class InetAddr
{
private:
    void ToHost(const struct sockaddr_in &addr)
    {
        _port = ntohs(addr.sin_port);
        _ip = inet_ntoa(addr.sin_addr);
    }

public:
    InetAddr(const struct sockaddr_in &addr):_addr(addr)
    {
        ToHost(addr);
    }
    std::string Ip()
    {
        return _ip;
    }
    uint16_t Port()
    {
        return _port;
    }
    ~InetAddr()
    {
    }

private:
    std::string _ip;
    uint16_t _port;
    struct sockaddr_in _addr;
};

UdpServer.hpp(服务端)

#pragma once

#include <iostream>
#include <unistd.h>
#include <string>
#include <cstring>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "nocopy.hpp"
#include "Log.hpp"
#include "InetAddr.hpp"

using namespace log_ns;

static const int gsockfd = -1;
static const uint16_t glocalport = 8888;

enum
{
    SOCKET_ERROR = 1,
    BIND_ERROR
};

// UdpServer user("192.1.1.1", 8899);
// 一般服务器主要是用来进行网络数据读取和写入的。IO的
// 服务器IO逻辑 和 业务逻辑 解耦
class UdpServer : public nocopy
{
public:
    UdpServer(uint16_t localport = glocalport)
        : _sockfd(gsockfd),
          _localport(localport),
          _isrunning(false)
    {
    }
    void InitServer()
    {
        // 1. 创建socket文件
        _sockfd = ::socket(AF_INET, SOCK_DGRAM, 0);
        if (_sockfd < 0)
        {
            LOG(FATAL, "socket error\n");
            exit(SOCKET_ERROR);
        }
        LOG(DEBUG, "socket create success, _sockfd: %d\n", _sockfd); // 3

        // 2. bind
        struct sockaddr_in local;
        memset(&local, 0, sizeof(local));
        local.sin_family = AF_INET;
        local.sin_port = htons(_localport);
        // local.sin_addr.s_addr = inet_addr(_localip.c_str()); // 1. 需要4字节IP 2. 需要网络序列的IP -- 暂时
        local.sin_addr.s_addr = INADDR_ANY; // 服务器端，进行任意IP地址绑定

        int n = ::bind(_sockfd, (struct sockaddr *)&local, sizeof(local));
        if (n < 0)
        {
            LOG(FATAL, "bind error\n");
            exit(BIND_ERROR);
        }
        LOG(DEBUG, "socket bind success\n");
    }
    void Start()
    {
        _isrunning = true;
        char inbuffer[1024];
        while (_isrunning)
        {
            struct sockaddr_in peer;
            socklen_t len = sizeof(peer);
            ssize_t n = recvfrom(_sockfd, inbuffer, sizeof(inbuffer) - 1, 0, (struct sockaddr *)&peer, &len);
            if (n > 0)
            {
                InetAddr addr(peer);
                inbuffer[n] = 0;
                std::cout << "[" << addr.Ip() << ":" << addr.Port() << "]# " << inbuffer << std::endl;


                std::string echo_string = "[udp_server echo] #";
                echo_string += inbuffer;
                sendto(_sockfd, echo_string.c_str(), echo_string.size(), 0, (struct sockaddr *)&peer, len);
            }
            else
            {
                std::cout << "recvfrom ,  error"  << std::endl;
            }
        }
    }
    ~UdpServer()
    {
        if(_sockfd > gsockfd) ::close(_sockfd);
    }

private:
    int _sockfd;
    uint16_t _localport;
    // std::string _localip; // TODO:后面专门要处理一下这个IP
    bool _isrunning;
};

云服务器上有很多IP，但是不能给我们绑定。所以我们所写的服务端无法具体绑定，所以我们只能绑定0（INADDR_ANY），代表服务端绑定了任意IP。所以客服端发送任意IP的8888端口号都能被服务端收到。

#define INADDR_ANY ((in_addr_t) 0x00000000)

UdpServerMain.cc(服务端主函数)

#include "UdpServer.hpp"

#include <memory>

// ./udp_server local-port
// ./udp_server 8888
int main(int argc, char *argv[])
{
    if(argc != 2)
    {
        std::cerr << "Usage: " << argv[0] << " local-port" << std::endl;
        exit(0);
    }
    uint16_t port = std::stoi(argv[1]);

    EnableScreen();  
    std::unique_ptr<UdpServer> usvr = std::make_unique<UdpServer>(port); //C++14的标准
    usvr->InitServer();
    usvr->Start();
    return 0;
}

UdpClientMain.cc(客户端主函数)

#include <iostream>
#include <string>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

// 客户端在未来一定要知道服务器的IP地址和端口号
// ./udp_client server-ip server-port
// ./udp_client 127.0.0.1 8888
int main(int argc, char *argv[])
{
    if(argc != 3)
    {
        std::cerr << "Usage: " << argv[0] << " server-ip server-port" << std::endl;
        exit(0);
    }

    std::string serverip = argv[1];
    uint16_t serverport = std::stoi(argv[2]);

    int sockfd = ::socket(AF_INET, SOCK_DGRAM, 0);
    if(sockfd < 0)
    {
        std::cerr << "create socket error" << std::endl;
        exit(1);
    }

    // client的端口号，一般不让用户自己设定，而是让client OS随机选择？怎么选择，什么时候选择呢？
    // client 需要 bind它自己的IP和端口， 但是client 不需要 “显示” bind它自己的IP和端口， 
    // client 在首次向服务器发送数据的时候，OS会自动给client bind它自己的IP和端口

    struct sockaddr_in server;
    memset(&server, 0, sizeof(server));
    server.sin_family = AF_INET;
    server.sin_port = htons(serverport);
    server.sin_addr.s_addr = inet_addr(serverip.c_str());
    while(1)
    {
        std::string line;
        std::cout << "Please Enter# ";
        std::getline(std::cin, line);

        // std::cout << "line message is@ " << line << std::endl;

        int n = sendto(sockfd, line.c_str(), line.size(), 0, (struct sockaddr*)&server, sizeof(server)); // 你要发送消息，你得知道你要发给谁啊！
        if(n > 0)
        {
            struct sockaddr_in temp;
            socklen_t len = sizeof(temp);
            char buffer[1024];
            int m = recvfrom(sockfd, buffer, sizeof(buffer)-1, 0, (struct sockaddr*)&temp, &len);
            if(m > 0)
            {
                buffer[m] = 0;
                std::cout << buffer << std::endl;
            }
            else
            {
                std::cout << "recvfrom error" << std::endl;
                break;
            }
        }
        else
        {
            std::cout << "sendto error" << std::endl;
            break;
        }
    }

    ::close(sockfd);
    return 0;
}

client的端口号，一般不让用户自己设定，而是让client OS随机选择？怎么选择，什么时候选择呢？

client 需要 bind它自己的IP和端口，但是client 不需要 “显示” bind它自己的IP和端口

client 在首次向服务器发送数据的时候，OS会自动给client bind它自己的IP和端口

V2 版本 - DictServer

实现一个简单的英译汉的网络字典

dict.txt

C++
apple: 苹果
banana: 香蕉
cat: 猫
dog: 狗
book: 书
pen: 笔
happy: 快乐的
sad: 悲伤的
run: 跑
jump: 跳
teacher: 老师
student: 学生
car: 汽车
bus: 公交车
love: 爱
hate: 恨
hello: 你好
goodbye: 再见
summer: 夏天
winter: 冬天

Dict.hpp

#pragma once
#include <iostream>
#include <string>
#include <fstream>
#include <unordered_map>
#include <unistd.h>
#include "Log.hpp"

using namespace log_ns;

const static std::string sep = ": ";

// sad: 悲伤的

class Dict
{
private:
    void LoadDict(const std::string &path)
    {
        std::ifstream in(path);
        if (!in.is_open())
        {
            LOG(FATAL, "open %s failed!\n", path.c_str());
            exit(1);
        }

        std::string line;
        while (std::getline(in, line))
        {
            LOG(DEBUG, "load info: %s , success\n", line.c_str());
            if (line.empty())
                continue;
            auto pos = line.find(sep);
            if (pos == std::string::npos)
                continue;

            std::string key = line.substr(0, pos);
            if (key.empty())
                continue;
            std::string value = line.substr(pos + sep.size());
            if (value.empty())
                continue;

            _dict.insert(std::make_pair(key, value));
        }
        LOG(INFO, "load %s done\n", path.c_str());
        in.close();
    }

public:
    Dict(const std::string &dict_path) : _dict_path(dict_path)
    {
        LoadDict(_dict_path);
    }
    std::string Translate(std::string word)
    {
        if(word.empty()) return "None";
        auto iter = _dict.find(word);
        if(iter == _dict.end()) return "None";
        else return iter->second;
    }
    ~Dict()
    {
    }

private:
    std::unordered_map<std::string, std::string> _dict;
    std::string _dict_path;
};

UdpServer.hpp

#pragma once

#include <iostream>
#include <unistd.h>
#include <string>
#include <cstring>
#include <functional>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include "nocopy.hpp"
#include "Log.hpp"
#include "InetAddr.hpp"

using namespace log_ns;

static const int gsockfd = -1;
static const uint16_t glocalport = 8888;

enum
{
    SOCKET_ERROR = 1,
    BIND_ERROR
};

using func_t = std::function<std::string(std::string)>;

// UdpServer user("192.1.1.1", 8899);
// 一般服务器主要是用来进行网络数据读取和写入的。IO的
// 服务器IO逻辑 和 业务逻辑 解耦
class UdpServer : public nocopy
{
public:
    UdpServer(func_t func, uint16_t localport = glocalport)
        : _func(func),
          _sockfd(gsockfd),
          _localport(localport),
          _isrunning(false)
    {
    }
    void InitServer()
    {
        // 1. 创建socket文件
        _sockfd = ::socket(AF_INET, SOCK_DGRAM, 0);
        if (_sockfd < 0)
        {
            LOG(FATAL, "socket error\n");
            exit(SOCKET_ERROR);
        }
        LOG(DEBUG, "socket create success, _sockfd: %d\n", _sockfd); // 3

        // 2. bind
        struct sockaddr_in local;
        memset(&local, 0, sizeof(local));
        local.sin_family = AF_INET;
        local.sin_port = htons(_localport);
        // local.sin_addr.s_addr = inet_addr(_localip.c_str()); // 1. 需要4字节IP 2. 需要网络序列的IP -- 暂时
        local.sin_addr.s_addr = INADDR_ANY; // 服务器端，进行任意IP地址绑定

        int n = ::bind(_sockfd, (struct sockaddr *)&local, sizeof(local));
        if (n < 0)
        {
            LOG(FATAL, "bind error\n");
            exit(BIND_ERROR);
        }
        LOG(DEBUG, "socket bind success\n");
    }
    void Start()
    {
        _isrunning = true;
        char inbuffer[1024];
        while (_isrunning)
        {
            struct sockaddr_in peer;
            socklen_t len = sizeof(peer);
            ssize_t n = recvfrom(_sockfd, inbuffer, sizeof(inbuffer) - 1, 0, (struct sockaddr *)&peer, &len);
            if (n > 0)
            {
                InetAddr addr(peer);
                inbuffer[n] = 0;
                // 一个一个的单词
                std::cout << "[" << addr.Ip() << ":" << addr.Port() << "]# " << inbuffer << std::endl;

                std::string result = _func(inbuffer);

                sendto(_sockfd, result.c_str(), result.size(), 0, (struct sockaddr *)&peer, len);
            }
            else
            {
                std::cout << "recvfrom ,  error" << std::endl;
            }
        }
    }
    ~UdpServer()
    {
        if (_sockfd > gsockfd)
            ::close(_sockfd);
    }

private:
    int _sockfd;
    uint16_t _localport;
    // std::string _localip; // TODO:后面专门要处理一下这个IP
    bool _isrunning;

    func_t _func;
};

利用回调函数进行翻译，传入对应的函数地址利用指针调用叫回调函数

InetAddr.hpp

#pragma once

#include <iostream>
#include <string>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

class InetAddr
{
private:
    void ToHost(const struct sockaddr_in &addr)
    {
        _port = ntohs(addr.sin_port);
        _ip = inet_ntoa(addr.sin_addr);
    }

public:
    InetAddr(const struct sockaddr_in &addr):_addr(addr)
    {
        ToHost(addr);
    }
    std::string Ip()
    {
        return _ip;
    }
    uint16_t Port()
    {
        return _port;
    }
    ~InetAddr()
    {
    }

private:
    std::string _ip;
    uint16_t _port;
    struct sockaddr_in _addr;
};

UdpServerMain.cc

#include "UdpServer.hpp"
#include "Dict.hpp"

#include <memory>

// ./udp_server local-port
// ./udp_server 8888
int main(int argc, char *argv[])
{
    if(argc != 2)
    {
        std::cerr << "Usage: " << argv[0] << " local-port" << std::endl;
        exit(0);
    }
    uint16_t port = std::stoi(argv[1]);
    EnableScreen();

    Dict dict("./dict.txt");
    func_t translate = std::bind(&Dict::Translate, &dict, std::placeholders::_1);
    
    std::unique_ptr<UdpServer> usvr = std::make_unique<UdpServer>(translate, port); //C++14的标准
    usvr->InitServer();
    usvr->Start();
    return 0;
}

UdpClientMain.cc

#include <iostream>
#include <string>
#include <cstring>
#include <unistd.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

// 客户端在未来一定要知道服务器的IP地址和端口号
// ./udp_client server-ip server-port
// ./udp_client 127.0.0.1 8888
int main(int argc, char *argv[])
{
    if(argc != 3)
    {
        std::cerr << "Usage: " << argv[0] << " server-ip server-port" << std::endl;
        exit(0);
    }

    std::string serverip = argv[1];
    uint16_t serverport = std::stoi(argv[2]);

    int sockfd = ::socket(AF_INET, SOCK_DGRAM, 0);
    if(sockfd < 0)
    {
        std::cerr << "create socket error" << std::endl;
        exit(1);
    }

    // client的端口号，一般不让用户自己设定，而是让client OS随机选择？怎么选择，什么时候选择呢？
    // client 需要 bind它自己的IP和端口， 但是client 不需要 “显示” bind它自己的IP和端口， 
    // client 在首次向服务器发送数据的时候，OS会自动给client bind它自己的IP和端口

    struct sockaddr_in server;
    memset(&server, 0, sizeof(server));
    server.sin_family = AF_INET;
    server.sin_port = htons(serverport);
    server.sin_addr.s_addr = inet_addr(serverip.c_str());
    while(1)
    {
        std::string line;
        std::cout << "Please Enter# ";
        std::getline(std::cin, line);

        // std::cout << "line message is@ " << line << std::endl;

        int n = sendto(sockfd, line.c_str(), line.size(), 0, (struct sockaddr*)&server, sizeof(server)); // 你要发送消息，你得知道你要发给谁啊！
        if(n > 0)
        {
            struct sockaddr_in temp;
            socklen_t len = sizeof(temp);
            char buffer[1024];
            int m = recvfrom(sockfd, buffer, sizeof(buffer)-1, 0, (struct sockaddr*)&temp, &len);
            if(m > 0)
            {
                buffer[m] = 0;
                std::cout << buffer << std::endl;
            }
            else
            {
                std::cout << "recvfrom error" << std::endl;
                break;
            }
        }
        else
        {
            std::cout << "sendto error" << std::endl;
            break;
        }
    }

    ::close(sockfd);
    return 0;
}

Socket 编程 UDP

V1 版本 - echo server

V2 版本 - DictServer

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